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Variation in Holocene El Niño frequencies: Climate records and cultural consequences in ancient Peru

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Abstract

Analysis of mollusks from archaeological sites on the north and central coasts of Peru indicates that between ca. 5800 and 3200 2800 cal yr B.P., El Niño events were less frequent than today, with modern, rapid recurrence intervals achieved only after that time. For several millennia prior to 5.8 ka, El Niño events had been absent or very different from today. The phenomena called El Niño have had severe consequences for the modern and colonial (historically recorded) inhabitants of Peru, and El Niño events also influenced prehistoric cultural development: the onset of El Niño events at 5.8 ka correlates temporally with the beginning of monumental temple construction on the Peruvian coast, and the increase in El Niño frequency after 3.2 2.8 ka correlates with the abandonment of monumental temples in the same region.

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... This data affords valuable insights into the environmental hardships encountered by Ushaped Buildings, as exemplified by instances observed at Manchay Bajo and Malpaso (Burger, 2009;Milan, 2014). The data aligns with the proposed escalation of ENSO events post-1200 BC, potentially contributing to the decline of the U-shaped Building tradition (Sandweiss et al., 2001). Similar assertions were put forth by Bird (Bird, 1987), who posited a significant ENSO event around 800 BC, and by Elera (Elera, 1998), who, based on the absence of mollusks adapted to the typical cold Peruvian waters at the Formative north coastal site of Puémape, inferred an ENSO event around 800 BC. ...
... These findings shed light on the environmental challenges faced by U-shaped buildings, such as those at Manchay Bajo and Malpaso (Burger, 2003;Milan, 2014). The data suggests an increase in ENSO events post-1200 BC, potentially contributing to the decline of the Ushaped building tradition (Sandweiss et al., 2001). Similar hypotheses have been proposed by Bird (Bird, 1987) and Elera (Elera, 1998), both identifying a significant ENSO event around 800 BC. ...
... Further research is necessary to understand the nature of this interaction (Burger and Salazar-Burger, 2023;Burger and Salazar, 2008) and the reasons behind the decline of the U-shaped building tradition between 1000 -500 cal BC. This period coincides with the Consolidation and Black and White phases at Chavín de Huántar (Kembel and Haas, 2015) (Kembel and Haas, 2015) and the occurrence of major ENSO phenomena (Bird, 1987;Elera, 1998;Sandweiss et al., 2001). ...
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This study presents an analysis of 190 radiocarbon dates derived from 13 Formative sites situated in the Andean Central Coast, specifically Lima, Peru, alongside an additional 59 dates obtained from the highland site of Chavín de Huántar. Bayesian statistical methods implemented through OxCal software are used for this analysis. The findings point towards the coexistence of Formative ceramic sites with previously identified Late Archaic sites (El Paraíso and Buena Vista). Additionally, the analysis highlights the persistent presence of a distinct architectural tradition characterized by U-shaped buildings across the central coastal landscape during the Andean Formative period. This architectural style reaches its zenith between 1500 and 1000 cal BC, followed by a gradual decline from 1000 to 500 cal BC, while also demonstrating significant temporal overlap with the prominent highland site of Chavín de Huántar from 1100 to cal 550 BC. This study provides a foundation for future research, pending the acquisition of additional dates in subsequent investigations.
... Coastal sites exploiting marine resources (fish, shellfish and edible seaweed types) traded with inland sites for agricultural and industrial crops, particularly cotton for fishing nets and lines, as well as gourds for net floats. In the Supe Valley alone, 18 sites ( Figure 4) evidenced the success of this economic exchange system [8][9][10][11][12][13][14][15][16] over long time periods (Figure 2), which experienced, and successfully survived, changes in environmental conditions brought about by Holocene sea level stabilization, Peru Current establishment and the increased frequency of El Niño flood events [17][18][19]. Again, major flood events were the basis for sedimentary beach ridge deposits inducing river drainage blockage, the creation of coastal marshlands behind drainage barriers, valley water-table height elevation and changes and aggraded sand sea formation behind and in front of beach ridges subject to aeolian sand transport and deposition, all of which influenced the agricultural and marine resource base of valley and coastal sites. Despite these challenges to the food resource base, societal continuity prevailed through relocations of agricultural field systems from coastal to inner valley areas over long time periods; only when ENSO events reached a level of severity without options to continue the food supply base that was sufficient to supply an increasing population did the coastal societies experience a challenge to their continuance. ...
... Sea-level stabilization between 6000 and 7000 cal BP set the stage for Late Archaic Period developments [5,19]. The onset of El Niño rains about 5800 cal BP after a mid-Holocene hiatus had implications for the social processes that found expression in the temple centers of Supe and the surrounding valleys [4,5,18,19]. ...
... Sea-level stabilization between 6000 and 7000 cal BP set the stage for Late Archaic Period developments [5,19]. The onset of El Niño rains about 5800 cal BP after a mid-Holocene hiatus had implications for the social processes that found expression in the temple centers of Supe and the surrounding valleys [4,5,18,19]. By~1500 BC, several preceramic north central coast sites were abandoned (Figure 2), suggesting a common influence of a large-scale environmental change affecting all areas of the Peruvian northcentral coast. ...
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The Late Archaic Period (2600–1600 BC) site of Caral, located ~20 km inland from the Pacific Ocean coastline in the Supe Valley of the north central coast of Peru, is subject to CFD analysis to determine the effects of ENSO (El Niño Southern Oscillation) events (mainly, El Niño flooding and drought events) on its agricultural and marine resource base that threatened societal continuity. The first step is to examine relics of major flood events that produced coastal beach ridges composed of deposited flood slurries—the C14 dating of material within beach ridges determines the approximate dates of major flood events. Of interest is the interaction of flood slurry with oceanic currents that produce a linear beach ridge as these events are controlled by fluid mechanics principles. CFD analysis provides the basis for beach ridge geometric linear shape. Concurrent with beach ridge formation from major flood events are landscape changes that affect the agricultural field system and marine resource food supply base of Caral and its satellite sites- here a large beach ridge can block river drainage, raise the groundwater level and, together with aeolian sand transfer from exposed beach flats, convert previously productive agricultural lands into swamps and marshes. One major flood event in ~1600 BC rendered coastal agricultural zones ineffective due to landscape erosion/deposition events together with altering the marine resource base from flood deposition over shellfish gathering and sardine and anchovy netting areas, the net result being that prior agricultural areas shifted to limited-size, inner valley bottomland areas. Agriculture, then supplied by highland sierra amuna reservoir water, led to a high water table supplemented by Supe River water to support agriculture. Later ENSO floods conveyed thin saturated bottomland soils and slurries to coastal areas to further reduce the agricultural base of Supe Valley sites. With the reduction in the inner valley agricultural area from continued flood events, agriculture, on a limited basis, shifted to the plateau area upon which urban Caral and the satellite sites were located. The narrative that follows then provides the basis for the abandonment of Caral and its satellite Supe Valley sites due to the vulnerability of the limited food-supply base subject to major ENSO events.
... The correlation between the increase in frequency of EI Nino and the start of a multi-centennial cessation of mound building is more tightly constrained in time, dating toward the end of the Initial period (-2900 cal BP). When we first identified the increase in EI Nino frequency from the biogeography of mollusks in north coast archaeological sites (D. Sandweiss et al. 2001), we could only place the change between about 3200 and 2800 cal BP. ...
... Three events occurred during mound use, between the pre-mound event and 3050-2950 cal BP. In our reconstruction of EI Nino for the north coast between 5800 and 2900 cal BP, event frequency is low, with large-magnitude events occurring only once or twice per century (D. Sandweiss et al. 2001). This is consistent with Nesbitt's event frequency at Caballo Muerto. ...
... Some support for this interpretation comes from Burger's excavations at Manchay Bajo (Burger 2003;D. Sandweiss et al. 2001), an Initial period site in the Lurin Valley near Lima. There, he found "evidence for EI Nino mitigation by temple leaders ... a major labor investment was made to construct a wall between the temple and the mouths of two ravines that can carry mudslide debris during EI Nino rainfall events" (D. Sandweiss et al. 2001, 605;Burger 2003). T ...
... Transformaciones ambientales claramente observables en los registros arqueológicos de los sitios ubicados en el litoral de la costa andina alrededor del 1100/1000 a.C., influenciadas por una mayor recurrencia de eventos ENSO en la costa, generaron inundaciones, lluvias y grandes movimientos poblacionales acompañados de subsecuentes heladas y sequias en la sierra. También se han propuesto notables cambios en el consumo de recursos marinos, especialmente observados en el caso de moluscos (Pozorski, 1976;Billman, 1996;Sandweiss et al., 2001). Estas crisis ambientales pueden haber sido uno de los muchos factores que contribuyeron al cese en la construcción y renovación de edificios monumentales (Sandweiss et al., 2001;Anderson et al, 2007). ...
... También se han propuesto notables cambios en el consumo de recursos marinos, especialmente observados en el caso de moluscos (Pozorski, 1976;Billman, 1996;Sandweiss et al., 2001). Estas crisis ambientales pueden haber sido uno de los muchos factores que contribuyeron al cese en la construcción y renovación de edificios monumentales (Sandweiss et al., 2001;Anderson et al, 2007). Lo anterior supone un importante postulado que parece tener una sólida correspondencia en el registro arqueológico, al menos en sitios del litoral ampliamente descritos y discutidos por Sandweiss y su equipo de investigación. ...
... Estas diferencias en relación con Gramalote pueden sugerir, o bien un cambio dramático en el consumo de bivalvos en la costa de Huanchaco a partir del 1100/1000 a.C., o que dichas especies no fueron tan consumidas en áreas asociadas a prácticas ceremoniales y funerarias, dado que no tenemos información de los rellenos de las ocupaciones domésticas que deben estar más hacia el oeste y hoy inaccesibles por las construcciones modernas del pueblo de Huanchaco. Sin embargo, nos gustaría sugerir que, en efecto, hubo un cambio dramático en el consumo de bivalvos en la costa de Huanchaco, lo que coincide con las observaciones hechas por Daniel Sandweiss quien ha sugerido que los cambios climáticos ocasionados por una mayor recurrencia de eventos ENSO, arrasaron con la presencia de especies de bivalvos de agua fría como el Choromytilus chorus (Sandweiss et al. 2001). De hecho, se ha podido reportar presencia de eventos ENSO asociados al Horizonte Temprano en el valle de Moche (Billman and Huckleberry 2008;Nesbitt 2016). ...
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En este artículo se presentan los primeros resultados de las investigaciones realizadas en el Sector José Olaya – Sitio Iglesia Colonial de Huanchaco, donde se ha registrado una ocupación del periodo Inicial Tardío y el Horizonte Temprano. En este artículo presentamos los datos de los contextos arqueológicos excavados, así como un análisis preliminar de la cerámica asociada, estudio de los restos malacológicos y algunos datos del análisis petrográfico. Al mismo tiempo, un análisis de la estratigrafía del sitio y 11 fechados AMS, ayudan a separar estas ocupaciones en tres subfases: José Olaya 1 (1000-800 a.C.), José Olaya 2 (800-600 a.C.) y José Olaya 3 (600-400 a.C.).
... The correlation between the increase in frequency of EI Nino and the start of a multi-centennial cessation of mound building is more tightly constrained in time, dating toward the end of the Initial period (-2900 cal BP). When we first identified the increase in EI Nino frequency from the biogeography of mollusks in north coast archaeological sites (D. Sandweiss et al. 2001), we could only place the change between about 3200 and 2800 cal BP. ...
... Three events occurred during mound use, between the pre-mound event and 3050-2950 cal BP. In our reconstruction of EI Nino for the north coast between 5800 and 2900 cal BP, event frequency is low, with large-magnitude events occurring only once or twice per century (D. Sandweiss et al. 2001). This is consistent with Nesbitt's event frequency at Caballo Muerto. ...
... Some support for this interpretation comes from Burger's excavations at Manchay Bajo (Burger 2003;D. Sandweiss et al. 2001), an Initial period site in the Lurin Valley near Lima. There, he found "evidence for EI Nino mitigation by temple leaders ... a major labor investment was made to construct a wall between the temple and the mouths of two ravines that can carry mudslide debris during EI Nino rainfall events" (D. Sandweiss et al. 2001, 605;Burger 2003). T ...
... Differential responses across west versus east facing slopes may partly explain this (Smith et al., 2009). Positive moisture anomalies at 4 ka BP have been linked to increased ENSO activity throughout the SCA, which was more pronounced compared to the Middle Holocene (Sandweiss et al., 2001;Mix et al., 2001;Donders et al., 2008). Even so, ENSO variability decreased between 4.5 and 3.5 ka BP compared to its variability after 3.5 ka BP (Sandweiss et al., 2001;Mix et al., 2001;Donders et al., 2008). ...
... Positive moisture anomalies at 4 ka BP have been linked to increased ENSO activity throughout the SCA, which was more pronounced compared to the Middle Holocene (Sandweiss et al., 2001;Mix et al., 2001;Donders et al., 2008). Even so, ENSO variability decreased between 4.5 and 3.5 ka BP compared to its variability after 3.5 ka BP (Sandweiss et al., 2001;Mix et al., 2001;Donders et al., 2008). Another possible explanation for increased moisture compared to the 6 ka BP has been linked to increased solar irradiance, which in turn would drive increased activity of the SASM at least on millennial timescales (Novello et al., 2016;De Porras et al., 2017). ...
Article
The long-term climate dynamics of the central Andes are part of an ongoing international research effort to reconstruct past climatic variations and sensitivity to different regional and global drivers during the last 50,000 years. The large number of diverse records, however, makes it difficult to compare results without an integrated spatial analysis that considers the nature of the record and whether they are integrating environmental conditions across a large basin (i.e., a lake record) or at a very local scale (such as a rodent midden). We compiled 92 records from the southern sector of the central Andes (SCA, 18-35 S). Recalibrated records were further compared by converting the original author's interpretation into a scale of relative moisture anomalies (compared to the present) that ranges from À2 (very dry) to very wet (þ2). Moisture anomaly maps were generated for intervals at 4, 6, 9.5, 14, 17, 21 and 32 ka BP (10 3 calibrated 14 C years before present) using records within a 5% age uncertainty. Our compilations show a surprising degree of agreement in the extent and magnitude of past climate changes during late Pleis-tocene, but less spatial agreement during the Holocene. The TRACE21 transient climate model shows similar results, with better agreement during the Pleistocene compared to the Holocene. Our analyses not only reveal discrepancies between proxy record interpretations at sites from the same region but show which regions in the SCA require more study.
... Continental and oceanic sedimentary archives and archaeological records indicate that the average climate and the activity and intensity of El Niño events were not constant during the Holocene [9,13,14,[27][28][29][30]. During the past two millennia in particular, three different phases occurred. ...
... However, unlike D. obesulus, M. donacium is particularly sensitive to changes in water temperature, and its populations decrease drastically and disappear during increases in SST caused by El Niño episodes [84]. Research by Sandweiss et al. [11,28,85] on malacological assemblages from several archaeological sites on the Peruvian coast shows that M. donacium is one of the most intensively economically exploited species since the end of the Pleistocene due to its extremely high biomass. Its presence in the shell middens of the northern sites is, however, discontinuous; indeed, it is present only under conditions of diminished frequency of El Niño events and disappears, replaced by the much smaller D. obesulus, when El Niño events occur with a frequency comparable to the present. ...
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Long considered on the margins, far from the major cultural traditions, the Sechura Desert is situated at the crossroads between the cultures of southern Ecuador and those of the northern Peruvian coast and preserves a large number of varied archaeological sites. Despite this evidence, little is known about the societies that inhabited this region during the Holocene. Exposed to natural hazards, including El Niño events, and to major climatic changes, they were able to adapt and exploit the scarce resources that this extreme environment offered them. Because of this rich history, we have been conducting archaeological research in this region since 2012 in order to clarify the dynamics of human occupation and their links with climate oscillations and environmental changes. This paper present the results of a multidisciplinary study of Huaca Grande, a mound located on Nunura Bay, 300 m from the Pacific Ocean. The nature of the human occupations at Huaca Grande was varied, and several adjustments occurred over time. The subsistence economy was based mainly on local marine resources and a continual use of terrestrial vegetal resources. However, a major change occurred in the more recent occupations, with the apparition of non-local resources (maize and cotton) indicating that Huaca Grande was connected to trade networks. The results show two main phases of occupation separated by a long abandonment (mid-5th century CE to mid-7th century CE and mid-13th century to mid-15th century CE). The occupation of the site appears to have been influenced by changes in the local climate and by extreme El Niño events. Our results highlight the great adaptability of these human groups over the span of a millennium and their capacity to react to the climatic changes and hazards that characterise this region.
... However, there is no agreement among scholars about which index best defines ENSO strength, timing, and duration, and fits severe precipitations satisfactorily [38,42,[52][53][54]. To address the change in frequency and intensity of events ascribed to El Niño events that hit the central Pacific coast of South America in pre-instrumental time, various approaches have been used, including geoarchaeological studies [10,55]. After the event of 1982/1983, scholars have focused on the power and occurrence of extremely strong events. ...
... Huckleberry and Billman [92] describe 13 ENSO-related flood and debris flow deposits beneath the present floodplain surface of Quebrada de los Chinos, which are younger than 2000 cal y BP. The findings of these authors seem to confirm the inference by Nials et al. [15] on apparent fluvial landscape changes due to severe precipitations (see Section 5.2), and reflect the late Holocene increases in El Niño activity [10,55]. With reference to methodological issues, the authors underline the need for a correct correlation between the geological characteristics of the deposits and the causative climatic events to make strong hypotheses [92]. ...
Article
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Coastal Peru, one of the driest deserts in the world, is a key region to investigate the connection between climate processes and Earth surface responses. However, the trends in space and time of the landscape effects of El Niño events throughout the last millennium are hard to outline. A deeper understanding of geological and archaeological data in pre-Hispanic time can help to shed light on some critical questions regarding the relationship between such a coupled atmosphere–ocean phenomenon and landscape modifications. The bibliographic sources required for this purpose are scattered throughout various disciplines, ranging from physical to human sciences, and thus comprehensive databases were used to identify and screen relevant studies. The performed examination of these documents allowed us to assess strengths and weaknesses of literature hypotheses and motivate additional studies on targeted research objectives.
... Molluscs found in archaeological sites on the north and central coasts of Peru provided the first clues that El Niño frequency had varied significantly throughout the Holocene. In the aggregate, available archaeological and palaeoclimatic data support a major change in tropical Pacific climate at about 5800 cal yr bp Sandweiss et al., , 2001, though it is unclear whether El Niño was absent or just extremely rare for several millennia prior to that date. Molluscan remains from Peru also suggest that between c. 5800 and 3000 cal yr bp, El Niño was present but less frequent than today. ...
... Archaeological and palaeontological deposits on the fossil beach and associated archaeological sites of the Ostra Complex, just north of the Santa River on the northcentral Peruvian coast (9˚S), date to about 5800 to 7150 cal yr bp Perrier et al., 1994;Andrus et al., 2003) (see Figure 4 for the location of the Ostra sites and other places mentioned in the text). Research at Ostra beginning in 1980 led to the hypothesis that the Ostra sites reflect a time when El Niño did not function as it does today Sandweiss et al., 1983Sandweiss et al., , 1997Sandweiss et al., , 1998aSandweiss et al., , 2001. ...
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Much of the early prehistory of the Americas lies underwater along its coastlines and in the submerged caves and cenotes of Florida and Central America. A cenote (from Yucatan Maya dzoonot ‘well’) is a deep natural pit, or sinkhole, resulting from the collapse of a doline or limestone bedrock that exposes groundwater underneath. Cenotes are a unique resource in a dry land, especially associated with the Yucatan Peninsula and some nearby Caribbean islands, and were sometimes used by the ancient Maya for sacrificial offerings. In times of lowered sea level and drier climate, as prevailed in the terminal Pleistocene, they were rare sources of freshwater for people and animals. Cenotes and the extensive cave systems to which they are linked have become the focus of palaeontological and palaeoanthropological studies by North American and Mexican Prehistorians, with the Vice-Directorate for Underwater Archaeology, National Institute of Anthropology and History (INAH) commanding several of these efforts. The search for early humans in the Yucatan Peninsula started more than a century ago when Henry Mercer arrived in search of early Americans; however, only in the last fifteen years have systematic efforts been undertaken. Efforts by archaeologists and cave-diving explorers have already resulted in the discovery of numerous assemblages of Pleistocene megafauna and pre-Maya humans. Finds near Tulum, Quintana Roo state, include some of the most complete early Americans skeletons, as well as a largely varied faunal complex including numerous examples of extinct megafauna. Some of the human skeletons are thought to be among the oldest in the hemisphere and they are so well preserved that now they are providing enough organic material for ancient DNA analysis and stable isotope studies. Associated concentrations of bat guano, wood, wood charcoal and calcite formations hold promise for advances in palaeoecology and sea-level history. Despite their great scientific value, these deposits are increasingly at risk from water pollution, salinization, tourism and urban development. As such dangers threaten inundated caves and cenotes all over the world, a major concern for UNESCO and other international and national agencies has been to set minimal standards for protecting this important heritage, which includes detailed recording at the sites and maintaining the materials in situ whenever possible.
... Molluscs found in archaeological sites on the north and central coasts of Peru provided the first clues that El Niño frequency had varied significantly throughout the Holocene. In the aggregate, available archaeological and palaeoclimatic data support a major change in tropical Pacific climate at about 5800 cal yr bp Sandweiss et al., , 2001, though it is unclear whether El Niño was absent or just extremely rare for several millennia prior to that date. Molluscan remains from Peru also suggest that between c. 5800 and 3000 cal yr bp, El Niño was present but less frequent than today. ...
... Archaeological and palaeontological deposits on the fossil beach and associated archaeological sites of the Ostra Complex, just north of the Santa River on the northcentral Peruvian coast (9˚S), date to about 5800 to 7150 cal yr bp Perrier et al., 1994;Andrus et al., 2003) (see Figure 4 for the location of the Ostra sites and other places mentioned in the text). Research at Ostra beginning in 1980 led to the hypothesis that the Ostra sites reflect a time when El Niño did not function as it does today Sandweiss et al., 1983Sandweiss et al., , 1997Sandweiss et al., , 1998aSandweiss et al., , 2001. ...
... Around the same time, an increase in sedentism and farming started to amplify the value and monopolizability of attractive and coercive resources, which the development of irrigation strengthened in the middle to late IP (figure 3). As the IP gave way to the EH, a new affordance developed on the Northern Coast: a gradual increase in the frequency and intensity of ENSO events [43,58]. These catastrophes devastated populations along some coastal sections but may have increased densities and political centralization in other, less affected sectors that took in displaced refugees [57], migrations that could explain the appearance of north-coast pottery on the south-central coast just as El Niño frequency increased [59]. ...
... At the IP/EH transition, monumental construction in North Coastal Peru virtually ceased [51], accompanied by considerable settlement abandonment and resettlement elsewhere. This may be attributable in part to an increasing frequency and intensity of ENSO events at this time [58]. However, the SPD points to a marked drop in population density in the centuries preceding this transition (figure 2), when ENSO events were occurring less frequently than after the IP/EH transition. ...
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Radiocarbon summed probability distribution (SPD) methods promise to illuminate the role of demography in shaping prehistoric social processes, but theories linking population indices to social organization are still uncommon. Here, we develop Power Theory, a formal model of political centralization that casts population density and size as key variables modulating the interactive capacity of political agents to construct power over others. To evaluate this argument, we generated an SPD from 755 radiocarbon dates for 10 000–1000 BP from Central, North Central and North Coast Peru, a period when Peruvian political form developed from ‘quasi-egalitarianism’ to state levels of political centralization. These data are congruent with theoretical expectations of the model but also point to an artefactual distortion previously unremarked in SPD research. This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.
... The archaeological site of the Sanctuary of Pachacamac (hereafter SP, 2nd to 16th centuries CE) is located on the central coast of Peru (Figures 1 and 2). SP covers an area of 465 hectares, and it is exposed to the events related to the El Niño-Southern Oscillation [26]. Heavy rain, intense winds, and hot airflow in the semiarid region of the Peruvian coast increased with the El Niño frequency over the last 3200-2800 years and were responsible for the abandonment of the coastal settlements in historical and prehistoric times [27]. ...
... The archaeological site of the Sanctuary of Pachacamac (hereafter SP, 2nd to 16th centuries CE) is located on the central coast of Peru (Figures 1 and 2). SP covers an area of 465 hectares, and it is exposed to the events related to the El Niño-Southern Oscillation [26]. Heavy rain, intense winds, and hot airflow in the semi-arid region of the Peruvian coast increased with the El Niño frequency over the last 3200-2800 years and were responsible for the abandonment of the coastal settlements in historical and prehistoric times [27]. ...
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Natural events (floods, earthquakes, landslides, etc.) may significantly damage archaeological sites, and therefore reducing their exposure to such events represents a priority for protective and conservation activities. The archaeological Sanctuary of Pachacamac (SP; 2nd–16th century CE; Peru) covers an area of 465 hectares and includes roads, enclosures, huacas with ramps, temples, and palaces located along the central coast of Peru. This area is affected by heavy rain and winds related to the El Niño–Southern Oscillation and to intense solar radiation. We use a 30 cm resolution Digital Surface Model obtained from orthophotogrammetric data and perform a morphometric analysis using geomorphological, hydrological, and climatic quantitative parameters. Our aim is to identify the zones exposed to water flow or stagnation during rainfall, as well as the exposure to winds and solar radiation. The calculated parameters are subsequently processed with an object-based image analysis approach to identify areas with higher climate exposure. We show that the SP architectural layout controls the exposure to water stagnation or flow in the form of rainfall, whereas exposure to wind and solar radiation mainly depends on the topography of an area (e.g., the presence of hills and plains). The methodological approach proposed here may be applied and extended to other archaeological sites.
... Elevated ENSO activity likely increases the probability of extreme events, which in turn increases the probability of soil destabilization and landslides. That ENSO is widely considered to have been less active in the mid-Holocene (Sandweiss et al., 2001;Moy et al., 2002;Rein et al., 2005;Mark et al., 2022) may be reflected in the reduced erosion documented at Progreso. ...
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Few paleoecological records are available to document the history of mid-elevation montane forests in the tropical Andes between 1500 and 2500 m above sea level. Archaeological studies have identified late-Holocene human modification of these landscapes, but it is not clear when and to what degree such alteration began. Here, we report fossil pollen, X-ray fluorescence, and charcoal data from Lake Progreso, which lies at 2013 m elevation in the eastern Peruvian Andes. The reconstruction of the effects of climate and human activity on an Andean lower montane forest is the first such high-resolution paleoecological record to span the Holocene. The record begins in the early Holocene, with lake formation in a forested setting that lacked fire. Marked erosive events were recorded in the early and late Holocene, but not the mid-Holocene. The first evidence of human disturbance in the record was the appearance of charcoal c. 6300 cal BP. This onset of burning was followed by maize cultivation c. 4520 cal BP. The basin surrounding Lake Progreso was disturbed and burned by humans intermittently thereafter but retained a predominance of forest throughout its history. The pollen, charcoal, and XRF data suggested that the site was generally used by small groups of people or settled by a small community. The Progreso record bore overall similarities in the timing of human occupation to records from nearby Lake Pomacochas, and the lower elevation site of Lake Sauce, though both those sites showed far greater deforestation. Collectively, these data suggested that Lake Progreso supported much smaller human populations and retained more of its forest than lakes Sauce or Pomacochas. While all sites shared a history of forest burning and maize cultivation, sufficient dissimilarities existed to indicate contrasting histories of site usage.
... The north coast of Peru is impacted by the El Niño phase of the El Niño Southern Oscillation (ENSO) phenomenon every 6-10 years. Archaeological and climate records point to a deep history of ENSO impacts on the coast, changing frequencies of events over time, and a diversity of 'flavours' of ENSO (Sandweiss et al. 1996(Sandweiss et al. , 2001Thompson et al. 1984, Waylen andCaviedes 1986). Eastern Pacific (EP) El Niños are the most well-known event type-these are characterized by warming in the central Pacific and weakened trade winds as waters move eastward. ...
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Scholarship on human–environment interactions tends to fall under two headings: collapse or resilience. While both offer valid explanatory frameworks for human–environment dynamics, both view stress as a net negative that, if unchecked, disrupts systems in equilibrium. Societies either succumb to stress (and collapse) or overcome stress and persist (demonstrate resilience). We re-evaluate the role of stress and advocate for a non-equilibrium approach to the study of past human–environment interactions. We draw inspiration from Nasim Taleb’s concept of ‘antifragility’, which posits a positive role of stress for increasingly complex systems. We apply antifragility as an explanatory framework to pre-Hispanic coastal Peru, where indigenous farmers adapted to the stresses of highly variable El Niño events through a variety of water management systems. Finally, we note that an antifragility approach highlights the beneficial role of stressors, and that avoiding stress altogether makes a system more fragile.
... Recent work in the Central Andes has demonstrated that climate change had a large impact on past diets, suggesting shifting climatic conditions altering local environments may explain a large portion of dietary change over the past 7000 years (Wilson et al., 2022). In this region, a strong body of work has also highlighted links between coastal subsistence, intensification, and climatic or environmental change (Parsons, 1970;Moseley, 1975;West, 1981;Sandweiss et al., 2001Sandweiss et al., , 2004Sandweiss et al., , 2009Dillehay and Kolata, 2004;Andrus et al., 2008;Reitz et al., 2008;Gerdau-Radonić et al., 2015;Tully et al., 2019;Goodbred et al., 2020). However much of this research is, necessarily, restricted in space or time, providing unique insights into individual and local experiences though not often capturing the overall history of human-environment interaction. ...
... Varios arqueólogos han señalado la importancia de El Niño al explicar los cambios en una cultura, de modo particular en la circunstancia de un «colapso» ( Van Buren 2001). En el caso específico del Periodo Inicial, Sandweiss y sus colegas (Sandweiss et al. 2001) sugieren que un aumento en la frecuencia de El Niño alrededor de 1100-800 a.C. (calib.) causó la declinación de las tradiciones de arquitectura monumental en la costa central y norte. ...
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En este artículo se presentan los resultados preliminares de la primera temporada de excavaciones en Huaca Cortada, complejo de Caballo Muerto, valle bajo de Moche. A pesar de que es uno de los edificios más grandes de dicho conjunto, hay poca información sobre su ocupación. El actual estudio, enfocado en varios aspectos de este tema, ofrece una comprensión más detallada de las fases de construcción y de su cronología. Se determinó que Huaca Cortada fue erigida alrededor de 1500 a.C. (calib.); sin embargo, la presencia de cerámica asociada a fases de una ocupación más tardía sugiere una historia más larga y compleja. Además, las excavaciones demuestran que el montículo fue construido en múltiples fases y con el objeto de aumentar sus dimensiones. Más aún, algunas fases tienen depósitos con sedimentos producidos por las fuertes lluvias asociadas al fenómeno de El Niño. Estas conclusiones desafían las afirmaciones previas, que indicaban que Huaca Cortada había sido levantada en una sola fase y bajo la dirección de una autoridad centralizada.
... La Niña results from abnormally cold SST in the eastern Pacific (Garreaud et al., 2003;Maasch, 2008;Quilter, 2014). Modern El Niño conditions were established by 3800-3200 cal yrs BP; however, no two ENSO events are the same and they can occur on different timescales depending on how severe the conditions are to be counted as a true El Niño event (Sandweiss, et al., 2001;Quilter, 2014;Fehren-Schmitz et al., 2014). Large-scale teleconnections across South America mean dynamics of SASM are also affected by ENSO variability, however the nature of these interactions over decadal to centennial timescales is still not fully understood (Henke et al., 2017: Kock et al., 2020. ...
Thesis
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This thesis provides new palaeoenvironmental data from the Peruvian Andes and develops our understanding of socio-economic responses to environmental and climatic changes within the Late Holocene. The three study areas of the Callejón de Huaylas (Ancash Region); Chillón Valley (Lima Region); Chicha-Soras Valley (Apurímac Region), provide a transect across the Andes to better understand regional differences in social responses to, and variations in, environmental change. The analysis of wetland records located within the key agricultural belt of the Peruvian Andes (3000-4000m a.s.l.), provide valuable records of past human land-use. By analysing palaeoecological (pollen, non-pollen palynomorphs, phytoliths and micro-charcoal) and geochemical (micro-XRF core scanning) signatures within these records, we can ascertain how past societies responded to known periods of major climate change, such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The results of this research have demonstrated that pre-Hispanic societies were able to cope with changes in climate by adapting agricultural practices, including the construction of reservoirs, agricultural terraces, and the use of wet pasture meadows (bofedales), and in doing so were able to deal with variability within natural resources, such as water availability. They also ensured the stability of their agricultural systems with continuity within the land-use records occurring over hundreds of years. It has also demonstrated considerable potential for high-resolution analysis of environmental change and the detection of both longer-scale regional climate change (MCA and LIA) and short-term climatic fluctuations (El Niño). Understanding how pre-Hispanic societies mitigated the risk posed by climate variability is important for future land-use, water, and soil conservation practices. The future preservation of the wetlands within the study is highly important for both climate change regulation and for conserving a valuable archive of human-environment interactions
... These data indicate that key changes occurred at around 5000 and again at 3000 BP towards more active ENSO cycles in the equatorial Pacific that were comparable to the high-amplitude fluctuations recorded during recent decades. Here, as in Southwest Asia, increased variability in climate and flood risk, along with unpredictable freshwater resources, seem to have been associated with a quickening pace of cultural development in the northern Andean region during the second half of the Holocene (Sandweiss et al. 2001), notwithstanding the difference in the overall trajectory of climate in this region towards wetter rather than drier conditions after ~5000 BP. ...
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Human societies have developed a wide range of strategies for coping with a variable natural environment that can lead to episodes of drought, frost, and flood, often linked to years of plenty and years of food scarcity. A Holocene perspective provides valuable insights into how human societies have coped with such climate changes in the past, some of them gradual, others more abrupt. During the late Pleistocene and early‐to‐mid Holocene, climate changes were determined by boundary conditions – such as solar radiation and ice cover – that were substantially different from those of today. The time period between ~8000 and 6000 BP represented a climatic optimum in many parts of the world. During the last few millennia, the boundary conditions controlling global climate became similar to those today, except for the sharp rise in atmospheric greenhouse gas concentrations during the industrial era.
... These lines of research engage with Andean archaeology in a special way, as many archaeologists have long tried to argue for a direct relationship between devastating ENSO episodes and social dynamics along the Peruvian coast (Nials et al., 1979;Moseley and Feldman, 1982;Sandweiss et al., 2001;Contreras 2010; among others). ...
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Today the Lower Ica Valley (Peru) exhibits evidence of environmental degradation, strong activity of deposition and erosion processes through modifying agents such as water and wind. All of this is the product of a long process of environmental transformation both during and since pre-Columbian times. Archaeological remains present in this valley evidence a long and important pre-Columbian cultural trajectory. We provide a case study of the geoarchaeology of the Samaca H-8 archaeological site that was founded sometime towards the end of the Middle Horizon (c. AD 900-1000) and consolidated its development during the Late Intermediate period (AD 1000-1400). This work contemplates the analysis of soils and sediments using micromorphology, geochemical-geophysical analyzes and radiocarbon dating. The results reveal that the construction and first occupation of Samaca H-8 (or at least the eastern part of the site), during the transition from the Middle Horizon period to the Late Intermediate Period, was marked by environmental dynamics and drastic landscape change toward more arid conditions. Recurrent deposition of windblown materials took place, perhaps due to a lack of protection offered by riparian dry forest cover. The Samaca H-8 site was established under these environmental conditions around AD 900.
... However, 97 there is no agreement among scholars about which index best defines ENSO strength, 98 timing, and duration, and fits severe precipitations satisfactorily well [33,37,[48][49][50]. To 99 address the change in frequency and intensity of events ascribed to El Niño that hit the 100 central Pacific coast of South America in pre-instrumental time, various approaches have 101 been used, including geoarchaeological studies [8,51]. After the event of 1982/83, scholars 102 focused on the power and occurrence of extremely strong events. ...
Preprint
The coastal Peru, one of the driest deserts in the world, has recently experienced dramatic landscape changes and asset destruction during precipitation events due to El Niño. Nevertheless, catastrophic explanations for landscape variations and human responses to the so-called "Super" or "Mega" El Niños are recurrent in pre-Hispanic time, even if alternative hypotheses were provided in literature. A deeper understanding of the geological and archaeological record can improve the knowledge on the relationship between such a coupled atmosphere-ocean phenomenon and landscape processes. The bibliographic sources required for this purpose are scattered throughout various disciplines ranging from physical to human sciences, thus comprehensive databases were used to identify and screen the relevant studies. The results provide knowledge synthesis in order to identify critical gaps and suggest specific research goals. Inferred episodes of landscape change due to severe precipitations in late pre-Hispanic time are discussed and consistencies and inconsistencies exposed. Examples of variation in landscape response due to extensive human intervention are reported.
... These ENSO-resistant species may have been exploited because they dominated regional intertidal shellfish communities under the climate conditions of the final centuries BCE. The increase in EP-EN frequency beginning approximately 1000 BCE eliminated the economically important but warm water sensitive taxa Mesodesma donacium and Choromytilus chorus north of 9°S and reduced their populations southward along a latitudinal gradient (Sandweiss et al., 2001. Both species became locally extinct in the Chincha Valley area following high magnitude El Niños in 1982-1983 and 1997-1998. ...
Article
The effects of El Niño Southern Oscillation (ENSO) are notoriously hazardous for human populations of the hyperarid Peruvian coast. Yet, ENSO climate fluctuations are fundamental to the ecology of desert plant and animal resources that have been incorporated into human subsistence economies for millennia. We examine marine shellfish exploitation among early complex societies in southern coastal Peru at the end of the first millenium BCE to better understand the subsistence vulnerability of communities in arid environments with variable resource availability and productivity. We analyze new shellfish data from Jahuay, a shoreline fishing settlement in the Topará Quebrada occupied amidst new regional social hierarchies and intensifying inner-valley agriculture. We compare mollusk taxonomic diversity and taxa rank order with published assemblages from four near-contemporaneous sites to assess local and regional trends in resource exploitation. At Jahuay, a unique focus on foraging plentiful Donax obesulus clams resistant to ENSO effects may reflect a local buffering strategy to ensure a resource supply through interannual and decadal climate oscillations. Our comparative results suggest regional reliance on intertidal resource patches, especially rocky habitats, for consumable shellfish. The relative convenience of gathering sessile intertidal taxa that form dense settlements may partly explain their regional popularity. The potential to dry and exchange mollusk meat as a protein source likely enhanced diet diversification while supporting economic and social relationships between communities. Overall, our findings imply that mollusks and intertidal foraging landscapes were important within a broad-spectrum subsistence strategy suited to maintaining and coordinating food availability in a dynamic environment.
... Reports from southern Peru suggest specific sites where mainly fish and seabird resources were exploited (Keefer et al. 1998), while at other (more ephemeral) sites they processed mainly molluscs (Sandweiss 2003). Studies from southern Peru and northern Chile demonstrated that the resources exploited by early coastal settlers of the HCS changed with time (Llagostera 1979, Sandweiss et al. 2001, which is taken as an indication of climate change and EN events, causing gradual or abrupt changes in available resources. Similar observations were made in central Chile near 32°S (Báez et al. 2004). ...
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The Humboldt Current System (HCS) is one of the most productive marine ecosystems on earth. It extends along the west coast of South America from southern Chile (~42 ° S) up to Ecuador and the Galapagos Islands near the equator. The general oceanography of the HCS is characterised by a predominant northward flow of surface waters of subantarctic origin and by strong upwelling of cool nutrient-rich subsurface waters of equatorial origin. Along the coast of northern and central Chile, upwelling is localised and its occurrence changes from being mostly continuous (aseasonal) in northern Chile to a more seasonal pattern in southern-central Chile. Several important upwelling centres along the Chilean coast are interspersed with long stretches of coast without or with sporadic and less intense upwelling. Large-scale climatic phenomena (El Niño Southern Oscillation, ENSO) are superimposed onto this regional pattern, which results in a high spatiotemporal heterogeneity, complicating the prediction of ecological processes along the Chilean coast. This limited predictability becomes particularly critical in light of increasing human activities during the past decades, at present mainly in the form of exploitation of renewable resources (fish, invertebrates and macroalgae). This review examines current knowledge of ecological processes in the HCS of northern and central Chile, with a particular focus on oceanographic factors and the influence of human activities, and further suggests conservation strategies for this high-priority large marine ecosystem. Along the Chilean coast, the injection of nutrients into surface waters through upwelling events results in extremely high primary production. This fuels zoo-plankton and fish production over extensive areas, which also supports higher trophic levels, including large populations of seabirds and marine mammals. Pelagic fisheries, typically concentrated near main upwelling centres (20-22 ° S, 32-34 ° S, 36-38 ° S), take an important share of the fish production, thereby affecting trophic interactions in the HCS. Interestingly, El Niño (EN) events in northern Chile do not appear to cause a dramatic decline in primary or zooplankton production but rather a shift in species composition, which affects trophic efficiency of and interactions among higher-level consumers. The low oxygen concentrations in subsurface waters of the HCS (oxygen-minimum zone, OMZ) influence predator-prey interactions in the plankton by preventing some species from migrating to deeper waters. The OMZ also has a strong effect on the bathymetric distribution of sublittoral soft-bottom communities along the Chilean coast. The few long-term studies available from sublittoral soft-bottom communities in northern and central Chile suggest that temporal dynamics in abundance and community composition are driven by interannual phenomena (EN and the extent and intensity of the OMZ) rather than by intra-annual (seasonal) patterns. Macrobenthic communities within the OMZ are often dominated in biomass by sulphide-oxidising, mat-forming bacteria. Though the contribution of these microbial communities to the total primary production of the system and their function in structuring OMZ communities is still scarcely known, they presumably play a key role, also in sustaining large populations of economically valuable crustaceans. Sublittoral hard bottoms in shallow waters are dominated by macroalgae and suspension feeder reefs, which concentrate planktonic resources (nutrients and suspended matter) and channel them into benthic food webs. These communities persist for many years and local extinctions appear to be mainly driven by large-scale events such as EN, which causes direct mortality of benthic organisms due to lack of nutrients/food, high water temperatures, or burial under terrigenous sediments from river runoff. Historic extinctions in combination with local conditions (e.g., vicinity to upwelling centres or substratum availability) produce a heterogeneous distribution pattern of benthic communities, which is also reflected in the diffuse biogeographic limits along the coast of northern-central Chile. Studies of population connectivity suggest that species with highly mobile planktonic dispersal stages maintain relatively continuous populations throughout most of the HCS, while populations of species with limited planktonic dispersal appear to feature high genetic structure over small spatial scales. The population dynamics of most species in the HCS are further influenced by geographic variation in propagule production (apparently caused by local differences in primary production), by temporal variation in recruit supply (caused by upwelling THE HUMBOLDT CURRENT SYSTEM OF NORTHERN AND CENTRAL CHILE 197 events, frontal systems and eddies), and topographically driven propagule retention (behind headlands , in bay systems and upwelling shadows). Adults as well as larval stages show a wide range of different physiological, ecological and reproductive adaptations. This diversity in life-history strategies in combination with the high variability in environmental conditions (currents, food availability, predation risk, environmental stress) causes strong fluctuations in stocks of both planktonic and benthic resources. At present, it remains difficult to predict many of these fluctuations , which poses particular challenges for the management of exploited resources and the conservation of biodiversity in the HCS. The high spatiotemporal variability in factors affecting ecological processes and the often-unpredictable outcome call for fine-scale monitoring of recruitment and stock dynamics. In order to translate this ecological information into sustainable use of resources, adaptive and co-participative management plans are recommended. Identification of areas with high biodiversity, source and sink regions for propagules and connectivity among local populations together with developing a systematic conservation planning, which incorporates decision support systems, are important tasks that need to be resolved in order to create an efficient network of Marine Protected Areas along the coast of northern-central Chile. Farther offshore, the continental shelf and the deep-sea trenches off the Chilean coast play an important role in bio-geochemical cycles, which may be highly sensitive to climatic change. Research in this area should be intensified, for which modern research vessels are required. Biodiversity inventories must be accompanied by efforts to foster taxonomic expertise and museum collections (which should integrate morphological and molecular information). Conservation goals set for the next decade can only be achieved with the incorporation of local stakeholders and the establishment of efficient administrative structures. The dynamic system of the HCS in northern-central Chile can only be understood and managed efficiently if a fluent communication between stakeholders, administrators, scientists and politicians is guaranteed.
... In others words, the model will predict that a fluctuating prevalence of D. pacificum and Anisakis infestations along the South American Pacific coast should be observed during the natural and cyclical ENSO phenomenon. Archaeological evidence of ENSO -Paleoclimatic data demonstrate climate variations in the Andean region during the Holocene period (Sandweiss et al. 2001 ). The Laguna Lejía, near San Pedro, in the Atacama desert shows that during the late glacial period i.e., 13,500-11,500 years ago, water resources were more abundant than today (Grosjean 1994 ). ...
Article
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Current clinical data show a clear relationship between the zoonosis rates of Diphyllobothrium pacificum and Anisakis caused by the El Niño Southern Oscillations (ENSO) phenomenon along the Chilean coast. These parasites are endemic to the region and have a specific habitat distribution. D. pacificum prefers the warmer waters in the northern coast, while Anisakis prefers the colder waters of Southern Chile. The ENSO phenomenon causes a drastic inversion in the seawater temperatures in this region, modifying both the cool nutrient-rich seawater and the local ecology. This causes a latitudinal shift in marine parasite distribution and prevalence, as well as drastic environmental changes. The abundance of human mummies and archaeological coastal sites in the Atacama Desert provides an excellent model to test the ENSO impact on antiquity. We review the clinical and archaeological literature debating to what extent these parasites affected the health of the Chinchorros, the earliest settlers of this region. We hypothesise the Chinchorro and their descendants were affected by this natural and cyclical ENSO phenomenon and should therefore present fluctuating rates of D. pacificum and Anisakis infestations.
... Seawater δ 18 O values can vary with evaporationprecipitation, ocean advection, upwelling, and fluvial input in coastal areas, all of which are influenced by El Niño-Southern Oscillation (ENSO) variability in coastal Peru. The ubiquitous presence of shortlived bivalves and other mollusk shells in Peruvian archaeological sites spanning the Holocene Epoch makes them uniquely positioned to leverage the reconstruction of past climatic shifts and variability coeval with human-environment dynamics (Carré et al., 2009;Sandweiss, 2003;Sandweiss and Kelley, 2012;Sandwess et al., 2001). ...
Article
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The coastline of Peru lacks long-lived marine organisms useful for paleoclimatic reconstructions generating a need for novel archives. Short-lived (<5 years) bivalves are commonly found in geological and archaeological deposits and thus can provide “snapshots” of past climatic variability (i.e., seasonal range), similar to data obtained by individual foraminifera analysis, rather than continuous, cross-dated time series (e.g., trees and corals). Previous studies have found success using the short-lived intertidal clam Mesodesma donacium. However, M. donacium are vulnerable to die-offs from the warmer sea surface temperatures (SST) associated with El Niño events and are functionally extinct in northern Peru thus limiting the possibility of modern analog studies for that region. Here we investigate the short-lived (1–3 years) surf clam, Donax obesulus, commonly found in northern Peru, as a paleoclimate archive. Dilophus obesulus populations are able to survive the warmer SSTs present during El Niño years although they are vulnerable to colder SSTs associated with La Niñas. We assessed the environmental drivers underlying subannual δ¹⁸O variability in D. obesulus from live collected shells from fish markets and coastal beaches near the Nepeña Valley, Peru in 2012 (La Niña), 2014 (ENSO-neutral), and 2016 (El Niño). Forward modeling of pseudo-shell δ¹⁸O reveals that SST variations are a dominant driver with secondary contributions from seasonally-varying seawater δ¹⁸O (δ¹⁸Osw). By accounting for varying δ¹⁸Osw, we isolated the temperature dependent variable resulting in a paleotemperature equation for D. obesulus δ¹⁸O. We verified our results with the δ¹⁸O record of a D. obesulus shell collected in 2006. Our results suggest that the paleotemperature equation we developed is useful for reconstructing El Niño-Southern Oscillation (ENSO)-related climatic variations in this region and the pseudo-shell approach may be useful for understanding shell δ¹⁸O in other locations.
... Alguns estudos realizados na barreira de coral de Huon (Urban et al., 2000), na Nova Guiné, parecem indicar que o fenômeno já existia, embora menos acentuado, há 130.000 anos. Outro estudo realizado conjuntamente pelas Universidades Yale, Pittsburgh, do Maine e de Miami (Sandweiss et al., 2001) sugere que um grave evento El Niño se verificou há cerca de 5.000 anos, e que há 3.000 anos verificou-se uma mudança nos ciclos, mudança esta que corresponde à alteração na seqüência das civilizações peruanas. ...
... In contrast, the Pacopampa case could be explained by an absence of social circumscription conditions, suggesting that violence was part of ceremonial actions (e.g., tinku) (Nagaoka et al., 2017). The coastal marine ecosystem began to be less predictable during the Formative epoch due to the increase in intensity and frequency of ENSO events (El Niño South Oscillation;Beresford-Jones et al. 2009;Beresford-Jones et al., 2015;Sandweiss et al., 2001). In northern Chile, Williams et al. (2008) used archaeological and paleoecological data to demonstrate a population decline between 4000 and 3000 cal year BP linked to ENSO, followed by a rapid increase 3000-2000 cal years BP coinciding with the introduction of horticulture and the concomitant socio-economic and cultural changes. ...
Article
The Neolithic or Formative Period in the New World drastically transformed the mode of production in human societies with the domestication of plants and animals. It impacted the way of life and social relations among individuals in permanent farming villages. Moreover, the emergence of elites and social inequality fostered interpersonal and inter- and intra-group violence associated with the defense of resources, socio-economic investments, and other cultural concerns. This study evaluated violence among the first horticulturalists in the Atacama Desert in northern Chile during the Neolithic transition between 1000 BCE – 600 CE. Furthermore, it analyzed trauma caused by interpersonal violence using a sample of 194 individuals. Strontium isotopic composition was examined to determine whether violence was local or among foreign parties. Settlement patterns, weapons, and rock art also were evaluated to assess expressions of violence. Skeletal and soft tissues presented the most direct evidence for violence. About 21% (n = 40) of adult individuals, particularly men, showed trauma compatible with interpersonal violence, with 50% (n = 20) of trauma appearing fatal. The findings suggested that violence was between local groups and that social and ecological constraints likely triggered violence within local communities.
... Instead, the Y-chromosomal and mitochondrial data demonstrate consistent patterns of population decline later in time, starting at around 125 generations ago i.e. 3.1 kya. This decline appears to temporally roughly coincide with a period of decreased solar irradiation ("The Homeric minimum") which has been associated to global climatic change, including heightened El Niño oscillation [73,74], and to major cultural shifts in Europe [75]. Interestingly, pollen and charcoal records from sediments of Lake Pomacochas in the Chachapoyas region demonstrate substantial changes in landscape around 3 kya, pointing somewhat paradoxically to heightened human activity. ...
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Many native populations in South America have been severely impacted by two relatively recent historical events, the Inca and the Spanish conquest. However decisive these disruptive events may have been, the populations and their gene pools have been shaped markedly also by the history prior to the conquests. This study focuses mainly on the Chachapoya peoples that inhabit the montane forests on the eastern slopes of the northern Peruvian Andes, but also includes three distinct neighboring populations (the Jívaro, the Huancas and the Cajamarca). By assessing mitochondrial, Y-chromosomal and autosomal diversity in the region, we explore questions that have emerged from archaeological and historical studies of the regional culture (s). These studies have shown, among others, that Chachapoyas was a crossroads for Coast-Andes-Amazon interactions since very early times. In this study, we examine the following questions: 1) was there pre-Hispanic genetic population substructure in the Chachapoyas sample? 2) did the Spanish conquest cause a more severe population decline on Chachapoyan males than on females? 3) can we detect different patterns of European gene flow in the Chachapoyas region? and, 4) did the demographic history in the Chachapoyas resemble the one from the Andean area? Despite cultural differences within the Chachapoyas region as shown by archaeological and ethnohistorical research, genetic markers show no significant evidence for past or current population substructure, although an Amazonian gene flow dynamic in the northern part of this territory is suggested. The data also indicates a bottleneck c. 25 generations ago that was more severe among males than females, as well as divergent population histories for populations in the Andean and Amazonian regions. In line with previous studies, we observe high genetic diversity in the Chachapoyas, despite the documented dramatic population declines. The diverse topography and great biodiversity of the northeastern Peruvian montane forests are potential contributing agents in shaping and maintaining the high genetic diversity in the Chachapoyas region.
... trabajos más sistemáticos están disponibles para la costa peruana o el extremo norte y centro de chile (carré et al. 2012;de Vries et al. 1997;gayo et al. 2012;grosjean et al. 2007;sandweiss et al. 1996, entre otros), pero la mayoría de ellos presenta escasa resolución para nuestra área de estudio. con todo, de acuerdo con los antecedentes disponibles, podríamos asumir un incremento en la intensidad y frecuencia de la variabilidad enos (el niño/oscilación del sur) durante la segunda mitad del Holoceno (andrus et al. 2008;de Vries et al. 1997;sandweiss et al. 2001;Vargas et al. 2006;Williams et al. 2008, entre otros), la que habría implicado un mayor impacto de lluvias torrenciales sobre la costa hiperárida del desierto de atacama a partir del 5500-5300 cal. ap (Vargas et al. 2006), favoreciendo la recarga de la mayoría de las actuales aguadas del litoral arreico, al menos de la zona de antofagasta y taltalpaposo (Herrera y custodio 2014). ...
... Paleoceanographic studies from the central and northern coast of Chile present general scenarios of dry and humid coastal conditions during the Middle Holocene (Grosjean et al. 2003(Grosjean et al. , 2007Gayo et al. 2012;Latorre et al. 2002Latorre et al. , 2005Rech et al. 2002) related to sea surface temperature variation (Carré et al. 2012;Kim et al. 2002) and ENSO events De Vries y Wells 1990;De Vries et al. 1997;Rollins et al. 1986;Sandweiss et al. 1996;Vargas et al. 2006). These studies show hyperarid conditions during the first half of the Middle Holocene and an increase in the intensity and frequency of ENSO events around 5800-5000 cal yr BP (Marchant et al. 1999;Sandweiss et al. 2001;Veit 1996;Andrus et al. 2008;Williams et al. 2008;Vargas et al. 2006). Present-day conditions were installed at the beginning of the Late Holocene, even though more humid pulses have been reported around 2500-2000 cal yr BP (Gayo et al. 2012). ...
Chapter
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Chapter 3 summarizes research on maritime adaptations at Middle Holocene (~7,500 to 4,500 cal BP) occupations of the southern extreme of the Atacama Desert, centered around Taltal on the north Chilean coast. Through this period, the authors see increasing population, complexity, and sedentism, but the social system comes to an abrupt end at 4,500 cal BP. In this hyperarid region, marine resources were always extremely important.
Chapter
The Cordillera Blanca is Earth’s most glacierized tropical mountain range. The current glaciers are receding and losing mass at accelerating rates, causing concerns for water resources and hazardous ice avalanches and potential for lake outburst flooding. The region features ample geomorphological evidence of much more extensive past glacial extent in the form of relict moraines and other glacial geological evidence extant on the landscape. Scientific interest in the glaciation initiated with mapping the extent of glaciers and their changes over time but has extended to explore the causes and broader socio-environmental implications of these changes. Scientists aim to glean further understanding of the climate forcing, but also to trace the flows of water resources as glacier recession has accelerated in recent decades and appreciate the dynamic relict landscape altered by glaciation. Ultimately how human society has adapted to existence in the region is tied to the legacy of glaciation in many ways.
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As arid lands expand across the globe, scholars increasingly turn to the archaeological record for examples of sustainable farming in extreme environments. The arid north coast of Peru was the setting of early and intensive irrigation-based farming; it is also periodically impacted by sudden, heavy rainfall related to the El Niño Southern Oscillation (ENSO) phenomenon. While the sociopolitical effects, technologies, and engineering expertise of these irrigation systems have been thoroughly examined and theorized, little is known about how farmers managed periods of water stress. The aim of this study is to test whether arid zone farming was supported by hybrid, intermittent flood and perennial water source systems in the prehispanic past. An arroyo in the Chicama Valley was selected for preliminary data collection, and these data are presented here: (1) drone photography of the arroyo capturing the aftermath of a recent (2023) rain event; and (2) potassium (K) soil test kit results from samples collected near suspected prehispanic check dam features in the same area. The paper combines these data with comparative examples from the literature to suggest that the prehispanic features functioned as water-harvesting infrastructure. The paper concludes that sustainable, arid zone farming can be supported by hybrid, intermittent flood and perennial water source systems.
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Relatively little attention has been paid to the importance of birds as alternative food sources and as ceremonial offerings in Moche practices. I examine bird remains from the Late Moche (600–900 CE) site of Huaca Colorada of the Jequetepeque Valley, Peru, to investigate the role of birds in daily activities and their use in ritual events.The Moche used birds in diverse ways in both domestic and ceremonial activities. Beginning with their use as food source, this analysis addresses the active hunting and opportunistic collection of various avian taxa to establish some of the ways that these animals formed part of subsistence practices. I further consider the way birds can serve as environmental proxies. I examine the presence of marine birds and possible nonlocal species at Huaca Colorada for their use in ceremonial practice. Zooarchaeological and iconographic evidence attests to various predatory bird taxa as important liminal beings for bridging different ecological zones and as vehicles for the travel of spirits and other supernatural forces between spheres of the living and the dead. By investigating birds in Moche practices, this article contributes new insights on the way avian species formed part of feasting events and mortuary offerings and more fully connects iconographic and zooarchaeological records.
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Doctrinal religions that involve recognised gods, more formal theologies, moral codes, dedicated religious spaces and professional priesthoods emerged in two phases during the Neolithic. Almost all of these appeared in a narrow latitudinal band (the northern Subtropical Zone). I suggest that these developments were the result of a need to facilitate community bonding in response to scalar stresses that developed as community sizes increased dramatically beyond those typical of hunter-gatherer societies. Conditions for population growth (as indexed by rainfall patterns and the difference between pathogen load and the length of the growing season) were uniquely optimised in this zone, creating an environment of ecological release in which populations could grow unusually rapidly. The relationship between latitude, religion and language in contemporary societies suggests that the peculiar characteristics of the northern (but not the southern) Subtropical Zone were especially favourable for the evolution of large scale religions as a way of enforcing community cohesion.
Article
The arid desert coast of northern Peru has traditionally been viewed either as existing in stasis, or as experiencing punctuated change from sudden flood events, followed by a return to system equilibrium. Despite these environmental extremes, the region was home to agriculture-based societies for millennia, and the success of these farming systems is considered an early example of irrigation technology transforming marginal landscapes. However, a closer examination of the long-term human-environment history of the Chicama Valley, one of the largest valleys in the coastal region, demonstrates that this landscape is the product of protracted interactions across at least three systems: the local environment, El Niño Southern Oscillation (ENSO), and farming. Here, El Niño floods, typically considered high-risk events, are fundamental to local biodiversity and renewal, resulting in a desert ecosystem that is both robust and elastic. The prehispanic farmland known as the Pampa de Mocan (1100BC–AD1460), is presented as a case study to observe the co-evolution of agricultural technology and an ENSO-hyper-arid environment. This ancient farming system developed the capacity to toggle between sudden floodwater inputs and periods of water scarcity. Alongside water and soil conservation practices, prehispanic agriculturalists implemented technologies that were designed to mitigate El Niño flooding and incorporate its byproducts to supplement available resources. The convergence of these interacting systems on the Pampa de Mocan offers new insights into the role of risk in building resilience.
Article
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The Lambayeque Valley on the north coast of Peru offers a cautionary case study on the relation between climatic and cultural change. Three archaeological site complexes dating from late in the first millennium AD to the middle of the second millennium AD rose and were abandoned in sequence. Each abandonment was associated with a conflagration on the main pyramidal mound(s). In this region, El Niño is the most significant climatic disruption now and for millennia past. By tracking proxy records for El Niño intensity, we found that only the first episode of abandonment and burning was associated with a strong peak in El Niño intensity, while the final episode was the outcome of the Spanish Conquest of the Andes, a distinctly non-climatic driver. These records suggest that equifinality is operative and urge caution in over-interpreting climate as culture-changing catastrophe.
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This is an appreciation of the life and work of invertebrate paleontologist. Harold B. Rollins emphasizing his contributions to our understanding of ENSO.
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Im Zeitraum 800 v. Chr. – 600 n. Chr. entwickelte sich in der heutigen Atacama-Küstenwüste von Peru die Paracas- und Nazca-Hochkultur mit ihren berühmten Geoglyphen (Scharrbilder). Der Anbau basierte auf einem ausgeklügelten Flussoasenbewässerungssystem und terrassiertem Ackerbau an den Gebirgshängen. Ab 500 n. Chr. wurde es trockener und ab 700 n. Chr. setzte eine langandauernde Trockenheit bis etwa 1150 n. Chr. ein, der Wüstenrand stieg bis auf 2000 m ü. M. nach Osten an. Damit trat ein Zerfall der Nazca-Kultur ein, fast alle Siedlungen wurden aufgegeben. In einem ökologisch fragilen Raum hinsichtlich der Wasserversorgung waren es vor allem Missernten mit Ernährungsprobleme durch die Megadürre mit Verlust von Prestige und Macht der lokalen Priesterfürsten wegen des ausbleibenden Regens, die den Kollaps der Hochkultur verursachten.
Article
Investigations at the site of Huacas de Moche—also referred to as Huacas del Sol and de la Luna—on the north coast of Peru show a continuous occupational sequence from around AD 100 to 1500. The longest occupation corresponds to the Moche culture from around AD 100 to 850. Based on available archaeological evidence, this article examines the impact of an El Niño-like event in AD 600 on the history of Huacas de Moche. Widely held hypotheses assumed that this kind of climatic event caused the abandonment of the site; however, such explanations do not fit the current data. After almost three decades of research, archaeological evidence indicates that after the El Niño-like phenomenon of AD 600, the Old Temple of Huaca de la Luna was closed down, and the New Temple was built toward the east of the previous one, on the same slope of Cerro Blanco. Furthermore, on the opposite side of the site, the building called Huaca del Sol experienced its last and greatest architectural expansion, becoming a large-scale palace. These new lines of evidence lead us to reassess the effect that the El Niño-like phenomenon of AD 600 had on the development of the Moche culture at the site.
Article
The Osmore Drainage of southern Peru has a long and rich history of human occupation. While the utility of stable oxygen and radiogenic strontium isotope values in identifying paleomobility between this region and population centers in the Bolivian altiplano has been well established, many questions about intra-regional mobility remain. To better understand how these methods can be used to detect localized residential mobility, we present new δ¹⁸Omw(VSMOW) and ⁸⁷Sr/⁸⁶Sr values from water, soil, plant, and faunal samples. Samples were collected primarily from traditionally farmed agricultural fields in the upper, middle, and lower Osmore Drainage. Results are indiscernible between the upper and middle drainage, while marine contribution to the lower drainage produces distinct values. We discuss the methodological limitations and implications of our results for the use of stable oxygen and radiogenic strontium isotope analyses for intra-regional paleomobility studies in the Osmore Drainage.
Article
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Measurements of oxygen isotopes and elemental ratios in a fossil coral that grew 124,000 years ago in North Sulawesi, Indonesia, reflect interannual variability in precipitation and sea surface temperature (SST) due to the El Niño/Southern Oscillation (ENSO). This indicates that ENSO was robust during the last interglacial period, a time when global climate was slightly warmer than the present. The pattern of ENSO frequency behavior in the past is similar to variability in modern instrumental records, but distinct from the most recent period since the mid-1970s, supporting the hypothesis that ENSO behavior in recent decades is anomalous with respect to natural variability.
Article
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Nilometers have been used for gauging the level of water in the Nile river for more than five millennia. The written records describing some of these measurements represent the longest written records for any hydrological phenomenon. They describe interannual fluctuations in the Nile river flow which are closely associated with El Niño phenomenon. Here, we use information about long-term variability in El Niño occurrences that has been extracted from the Nilometers records to test the significance of the recent trend in the frequency of El Niño years. We show that the observed frequency of El Niño years during the last two decades is rather high compared to the long-term statistics that are computed from about a thousand years of Nilometers data; however similar levels of activity have been observed during the first millennium.
Article
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A number of recent reports have interpreted paleoproxy data to describe the state of the tropical Pacific, especially changes in the behavior of the El Niño-Southern Oscillation (ENSO), over the Holocene. These interpretations are often contradictory, especially for the eastern tropical Pacific and adjacent areas of South America. Here we suggest a picture of the mid-Holocene tropical Pacific region which reconciles the data. ENSO variability was present throughout the Holocene but underwent a steady increase from the mid-Holocene to the present. In the mid-Holocene, extreme warm El Niño events were smaller in amplitude and occurred less frequently about a mean climate state with a cold eastern equatorial Pacific and largely arid coastal regions as in the present climate. This picture emerges from an experiment in which a simple numerical model of the coupled ocean-atmosphere system in the tropical Pacific was driven by orbital forcing. We suggest that the observed behavior of the tropical Pacific climate over the mid- to late Holocene is largely the response to orbitally driven changes in the seasonal cycle of solar radiation in the tropics, which dominates extratropical influences.
Article
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The archaeological site of Quebrada Tacahuay, Peru, dates to 12,700 to 12,500 calibrated years before the present (10,770 to 10,530 carbon-14 years before the present). It contains some of the oldest evidence of maritime-based economic activity in the New World. Recovered materials include a hearth, lithic cutting tools and flakes, and abundant processed marine fauna, primarily seabirds and fish. Sediments below and above the occupation layer were probably generated by El Niño events, indicating that El Niño was active during the Pleistocene as well as during the early and middle Holocene.
Article
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Sedimentological, mineralogical and geochemical analyses of sediment cores from 9 m-deep, saline Laguna Miscanti, Chile (23 44S, 67 46W, 4140 m a.s.l.) together with high-resolution seismic profiles provide a mid to late Holocene time series of regional environmental change in the Atacama Altiplano constrained by 210Pb and conventional 14C dating. The mid Holocene was the most arid interval since the last glacial maximum, as documented by subaerial exposure and formation of hardgrounds on a playa surface. Extremely low lake levels during the mid Holocene appear consistent with lower effective moisture recorded at other sites along the Altiplano and in the Amazon Basin. Termination of this arid period represented a major shift in the regional environmental dynamics and inaugurated modern atmospheric conditions. The cores show a progressive upward increase in effective moisture interrupted by numerous century-scale drier periods of various intensities and durations that characterize a fluctuating late Holocene climate. In spite of chronological uncertainties, the major environmental changes seem to correlate with the available paleorecords from the region providing a coherent account of effective moisture variability in the tropical highlands of South America.
Article
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Copper and gold artifacts in contexts dated to ∼3120 to 3020 carbon-14 years before the present (∼1410 to 1090 calendar years B.C.) recovered in excavations at Mina Perdida, Lurı́n Valley, Peru, show that artisans hammered native metals into thin foils, in some cases with intermediate anneals. They gilded copper artifacts by attaching gold foil. The artifacts show that fundamental elements of the Andean metallurgical tradition were developed before the Chavı́n horizon, and that on the Peruvian coast the working of native copper preceded the production of smelted copper objects.
Article
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Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Niño events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2 to 8.5 years. This is the modern El Niño periodicity, which was established about 5000 calendar years before the present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.
Article
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A glacial varve chronology from New England spanning the 4000-year period from 17,500 to 13,500 calendar years before the present was analyzed for evidence of climate variability during the late Pleistocene. The chronology shows a distinct interannual (3 to 5 years) band of enhanced variability suggestive of El Nino-Southern Oscillation (ENSO) teleconnections into North America during the late Pleistocene, when the Laurentide ice sheet was near its maximum extent and climatic boundary conditions were different than those of today. This interannual variability largely disappears by the young end of the 4000-year chronology, with only the highest frequency components (roughly 3-year period) persisting. This record provides evidence of ENSO-like climate variability during near-peak glacial conditions.
Article
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Fossil rodent middens and wetland deposits from the central Atacama Desert (22 degrees to 24 degrees S) indicate increasing summer precipitation, grass cover, and groundwater levels from 16.2 to 10.5 calendar kiloyears before present (ky B.P.). Higher elevation shrubs and summer-flowering grasses expanded downslope across what is now the edge of Absolute Desert, a broad expanse now largely devoid of rainfall and vegetation. Paradoxically, this pluvial period coincided with the summer insolation minimum and reduced adiabatic heating over the central Andes. Summer precipitation over the central Andes and central Atacama may depend on remote teleconnections between seasonal insolation forcing in both hemispheres, the Asian monsoon, and Pacific sea surface temperature gradients. A less pronounced episode of higher groundwater levels in the central Atacama from 8 to 3 ky B.P. conflicts with an extreme lowstand of Lake Titicaca, indicating either different climatic forcing or different response times and sensitivities to climatic change.
Article
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The El Niño-Southern Oscillation (ENSO) is the most potent source of interannual climate variability. Uncertainty surrounding the impact of greenhouse warming on ENSO strength and frequency has stimulated efforts to develop a better understanding of the sensitivity of ENSO to climate change. Here we use annually banded corals from Papua New Guinea to show that ENSO has existed for the past 130,000 years, operating even during "glacial" times of substantially reduced regional and global temperature and changed solar forcing. However, we also find that during the 20th century ENSO has been strong compared with ENSO of previous cool (glacial) and warm (interglacial) times. The observed pattern of change in amplitude may be due to the combined effects of ENSO dampening during cool glacial conditions and ENSO forcing by precessional orbital variations.
Article
ENSO variability produces distinct thermal and chemical signals in the surface ocean. Shallow-growing corals from sensitive Pacific sites incorporate these anomalies in the isotopic and trace metal chemistry of their aragonite skeletons. Short (~20 yr) coral records provide independent monitors of the ENSO system at three sites across the Pacific basin: the Galapagos (1°S, 91°W), Tarawa Atoll (1°N, 173°E), and Bali (8°S, 115°E). Galapagos Cd/Ca, Ba/Ca, and δ¹⁸O records reflect the degree of regional upwelling in the eastern Pacific, which is suppressed during warm ENSO conditions. Oxygen isotopic data from Tarawa Atoll corals record the intense precipitation that the eastward displacement of the Indonesian Low brings to this region during warm ENSO periods. An independent record of Mn/Ca from one of these corals reflects the weakening and reversal of the trade winds that may trigger the onset of warm ENSO conditions basinwide. Finally, δ¹⁸O from a Bali coral reflects the weakening of the Indonesian monsoon associated with warm ENSO periods. -from Authors
Article
The Casma Valley contains the largest New World structure of its time period 2500 to 200 BC. The preliminary results of excavation and survey at 15 sites are described, each site dated, and assessments of this important valley's diet and subsistence changes through time are discussed. Divided into 3 main sections the chapters cover: Casma Valley sites excavated in 1980; early sites surveyed within the Casma Valley; the prehistory of the Casma Valley and its impact on studies of early Andean prehistory. -K.Riches
Chapter
Examination of the charcoal particle stratigraphy in sediment cores from seven meadows from the Sierra Nevada of California allows reconstruction of regional fire periods and their relationship to climate during the Holocene. With the exception of the period of 8700 to 9200 yr BP, charcoal is less frequently encountered in early Holocene sediments than it is in sediments deposited after 4500 yr BP. We hypothesize a climatic control. Empirical and modeled data suggest that the early Holocene was xerothermic in the Sierra Nevada. Pollen evidence suggests forests were more open than today, thus producing less tree biomass for fuel. Intensification of El Niño during the middle Holocene may have been important in changing the character of the Sierran forests as well.
Article
A critical evaluation of radiocarbon measurements taken from recent excavations at Chavin de Huantar, Peru provides the basis for an absolute chronology for the Chavin culture at Chavin de Huantar which spans from 850 B.C. to 200 B.C. Radiocarbon measurements from four coastal sites stylistically related to Chavin de Huantar are reviewed and found to be generally prior in date to the earliest known occupation at Chavin de Huantar.
Article
The 1987/1988 field season at the U-shaped civic ceremonial center of Cardal in the Lurin Valley, Peru, included mapping and excavation of public and domestic architecture. Occupied from 1150 to 800 b.c., Cardal provides evidence of a more elaborate ground plan than was previously recognized, including dual causewayed plazas, and 10 semisubterranean circular courts. Excavations of the public architecture revealed the periodic burial and construction of ritual buildings, including a steep central stairway and an atrium whose exterior wall was decorated with a polychrome mural of a gigantic mouth band with massive fangs and interlocking teeth. The investigations on the pyramid summit also yielded evidence of a free-standing building with a dual altar, and a burial area. Information on domestic architecture and subsistence recovered from behind the public complex is also discussed. Finally, Cardal is compared to Garagay, a coeval U-shaped center in the neighboring Rimac Valley, and it is argued that the evidence available does not support the hypothesis that these monumental centers were constructed by “complex societies” in the traditional sense of the term.
Article
The Age Calibration Program, CALIB, published in 1986 and amended in 1987 is here amended anew. The program is available on a floppy disk in this publication. The new calibration data set covers nearly 22 000 Cal yr (approx 18 400 14C yr) and represents a 6 yr timescale calibration effort by several laboratories. The data are described and the program outlined. -K.Clayton
Article
Significant precipitation along the north-central coast of Peru (lat 5°-10°S) occurs exclusively during El Niño incursions of warm water into the Peruvian littoral. Flood deposits from this region therefore provide a proxy record of extreme El Niño events. I present a 3500 yr chronology of the extreme events based on radiocarbon dating of overbank flood sediments from the Rio Casma (lat 9.2°S).The flood-plain stratigraphy suggests that the El Niño phenomenon has occurred throughout the Holocene and that flood events much larger than that which occurred during 1982-1983 occur here at least once every 1000 yr.
Article
The upper temperature tolerance of 10 commercially important South American bivalve species (Gari solida, Semele solida, Semele corrugata, Protothaca thaca, Venus antiqua, Tagelus dombeii, Ensis macha, Aulacomya ater, Choromytilus chorus and Argopecten purpuratus) off Peru and Chile was determined and compared in order to study some of the effects of El Nino. Due to higher habitat temperatures in Peru, LT50 (lethal temperatures for 50 % of an experimental population) are higher than in Chile. In Chile LT50 for 6 of 8 species studied varied only by 1.2-degrees-C. This might be explained by the similar temperatures and living conditions in the habitats of these species. Especially for Peru, observed differences in LT50 could be related to different geographical distributions. For all species temperature increases recorded during the strongest El Nino of this century (1982-83) did not exceed the temperature tolerance interval, = (difference between LT50 after 24 h and mean annual water temperature). It is noted that all species studied here are tolerant of temperature conditions occurring during moderate El Nino events.
Article
Annual variations in the amount and chemical composition of precipitation accumulating on tropical and subtropical ice caps produce annual laminations which allow precise dating of these stratigraphic sequences. The thickness of an annual lamination reflects the net accumulation, while the physical and chemical constituents (eg dust, isotopes, ions) record local atmospheric conditions during deposition. In this chapter interannual climate variability is reconstructed from ice cores on the tropical Quelccaya ice cap, Peru, and the subtropical Dunde ice cap, China. Except of the annual cycle, the El Nino/Southern Oscillation (ENSO) is the dominant signal in the global climate system on time scales of months to several years. We detect low-frequency teleconnections across the Pacific Basin through the Walker Circulation. -from Authors
Article
The Holocene climatic history of tropical northern Australia is re-examined using the recently published pollen record from Groote Eylandt to corroborate and refine previous climatic inter pretations. We identify a four-stage Holocene comprising: (1) a continuous increase in effective precipitation (EP) from the beginning of the Holocene to about 5000 BP; (2) a mid-Holocene EP maximum from about 5000 to about 4000 BP; (3) a marked decline in EP somewhere between 4000-3500 Bp; and (4) an EP recovery in the last <2000 years. The mid-Holocene EP maximum is 1000 years later than Holocene EP maxima from temperate Southern Australia and suggests that the records are decoupled at this time. We focus on pollen evidence of environmental change at c. 4000 BP, which marks a break between a continuously ameliorating (increasing EP) climate but with small mean variation in the earlier Holocene and a steady (no directional trend) but highly variable later Holocene. We believe that this break represents the first evidence from the monsoonal lowlands of northern Australia for the onset of 'modern' ENSO-dominated ocean-atmosphere interactions in the Holocene. A simple conceptual model of trans-Pacific teleconnections is presented to explain this onset and as an hypothesis for testing.
Article
The dominant effect of El Nino/Southern Oscillation (ENSO) on amphi-South Pacific climates is to increase the variability of precipitation. The characteristic climate pattterns which accompany the alternating phases of ENSO are opposed in the eastern and western Pacific. Broadly speaking, in Australasia droughts accompany El Nino events, and wetter than average conditions accompany La Nina events, whereas in western South America south of the equator, wet conditions characterize El Nino and drier conditions characterize La Nina events. New Zealand and southern South American climates are somewhat cooler during El Nino events. The generally more stable climates of the early Holocene period and lack of comparable precipitation patterns in the amphi-South Pacific land areas point to either a much reduced amplitude of the ENSO fluctuations, or to a change in the extratropical expression of ENSO due to different climatic boundary conditions. -from Authors
Article
Fourteen organic-rich sedimentary layers in the deposits at Quebrada de los Burros, in coastal southern Peru (Tacna department), lie between two debris-flow units, interpreted to result from El Niño events, at 8980 cal yr B.P. and after 3380 cal yr B.P., respectively. The accumulation of the fine-grained and low-energy sediments of this deposit during the mid-Holocene is incompatible with the occurrence of El Niño events in this region, as these would produce catastrophic flood deposits. The occurrence of organic-rich sediments and evidence of an enhancement of upwelling strength at this time imply the existence of a permanent water supply resulting from an increased condensation of fog at mid-altitudes. These results suggest a lower intensity and, perhaps, a lower frequency of occurrence of the El Niño phenomenon during the mid-Holocene. It is precisely during this period that the most important human settlements are found at this site, probably indicating the presence of reliable supply of fresh water. The chronologies for wetlands in the central south altiplano are out of phase with those indicating increased soil moisture episodes on the coast, implying a long-term difference in climate between these two regions.
Article
Data from the El Junco lake suggest that the climate of the eastern Pacific Ocean in glacial and postglacial times correlated with climatic events in the northern hemisphere.
Article
Paleoenvironmental data from the Atacama Altiplano (21°–24°S) indicate that water, vegetation and animal resources were more abundant during lateglacial and early Holocene times than today. The rate of precipitation increased above 4000 m elevation to 400–500 mm/yr compared to the present 200 mm/yr. Dry conditions prevailed below 3500 m. Evidence of Paleoindian habitation is still missing, even though there is no evidence for environmental prohibitors during lateglacial time. The early Archaic hunters (10,820 yr B.P.-ca. 8500 yr B.P.) inhabited the Altiplano (high Puna) and its western slope, where water was available due to higher river runoff from the Altiplano, and the resources in different elevation zones were accessible. Natural resources decreased significantly during the middle Archaic period (8500-ca. 5000 yr B.P.). Lakes receded to today's levels, pedogenesis in the Altiplano terminated, and human activities were restricted to the most stable sites in the Río Lao and the Río Purifica catchments north of 23°S. The less stable oases south of 23°S (Salar de Atacama and Punta Negra) were abandoned. The climatic changes are best explained by shifts of the (sub)tropical circulation. © 1994 John Wiley & Sons, Inc.
Article
In the Norte Chico precipitation is controlled by atmospheric perturbations and frontal systems associated with the belt of westerly wind circulation. The Holocene climatic history of the region can be reconstructed from geomorphic and pedologic investigations. In comparison to modern climatic conditions, increased influence of the westerlies is deduced for the time periods prior to 7300 yr B.P., between 5000-3700 yr B.P., 3000-1800 yr B.P. and around 270 yr B.P. It remains uncertain whether the increased influence of the westerlies was the consequence of northward shifts of the westerlies as a whole, of a meridional expansion of the westerly belt, or only of intensity changes of the atmospheric dynamics. Almost synchronous with changes in the westerlies the coastal fogs in the region were apparently reduced or the fog belt in the coastal range was elevated, probably due to a weakened upwelling and warmer water conditions in the eastern Pacific. In general, the climate of the Norte Chico has become more variable since 5000 yr B.P., especially since 3000 yr B.P., with frequent changes of the geoecological conditions.
Article
A high resolution sedimentary record spanning the last deglacial and Holocene periods was obtained by studying the deep-sea sediment core GIK 17748-2 retrieved from 2545 m water depth in the Valparaiso Basin (Chilean continental slope, Southeast Pacific — 32°45.00′S; 72°02.00′W). AMS- measurements and oxygen-isotope analyses of the planktic foraminifera species Globigerina bulloides and Neogloboquadrina pachyderma (dex.) indicate an age of 13.3 AMS- kyr B.P. at the base of the core (383 cm) and sedimentation rates ranging between 9 and 92 cm/kyr. Foraminiferal assemblages and accumulation rates were analysed in order to investigate variations in paleoceanography and paleoproductivity in the southern Peru–Chile Current during the last 13 kyr. Changes in foraminiferal assemblages indicate a sequence of three major hydrographic regimes at the site of the core: (1) deglacial sediments are characterised by variable faunal compositions generally reflecting strong upwelling and high productivity. (2) During the early and middle Holocene upwelling and, thus, productivity decreased, as indicated by an elevated relative abundance of N. pachyderma (dex.), and the importance of the Subtropical Surface Water of the Peru–Chile Countercurrent increased, as indicated by higher relative amounts of N. dutertrei. (3) For the last 3 kyr, variable faunal assemblages indicate variable competing environmental conditions characterised on one hand by increased upwelling, reflected by an elevated relative abundance of N. pachyderma (sin.), and on the other hand, by warmer conditions, deduced from a higher relative abundance of N. dutertrei, probably due to more frequent and more intense El Niño events. In addition, hints for slightly cooler conditions between 11.4 and 10.7 kyr B.P. might be related to a Younger Dryas event in this region.
Article
Sediment cores collected from the southern basin of Lake Titicaca (Bolivia/Peru) on a transect from 4.6 m above overflow level to 15.1 m below overflow level are used to identify a new century-scale chronology of Holocene lake-level variations. The results indicate that lithologic and geochemical analyses on a transect of cores can be used to identify and date century-scale lake-level changes. Detailed sedimentary analyses of subfacies and radiocarbon dating were conducted on four representative cores. A chronology based on 60 accelerator mass spectrometer radiocarbon measurements constrains the timing of water-level fluctuations. Two methods were used to estimate the14C reservoir age. Both indicate that it has remained nearly constant at ∼25014C yr during the late Holocene. Core studies based on lithology and geochemistry establish the timing and magnitude of five periods of low lake level, implying negative moisture balance for the northern Andean altiplano over the last 3500 cal yr. Between 3500 and 3350 cal yr B.P., a transition from massive, inorganic-clay facies to laminated organic-matter-rich silts in each of the four cores signals a water-level rise after a prolonged mid-Holocene dry phase. Evidence of other significant low lake levels occurs 2900–2800, 2400–2200, 2000–1700, and 900–500 cal yr B.P. Several of the low lake levels coincided with cultural changes in the region, including the collapse of the Tiwanaku civilization.
Article
For the tropical west coast of South America, where El Niño/Southern Oscillation (ENSO) is most pronounced, archaeological and associated paleontological deposits in northern Peru revealed a major climate change at about 5000 years before the present (yr B.P.). The data implied the presence of stable, warm tropical water as far south as 10°S during the early mid-Holocene (about 8000 to 5000 yr B.P.). These data suggest that ENSO did not occur for some millennia preceding 5000 yr B.P., when global and regional climate was warmer than today.
Article
A study of plant and animal remains from eleven archaeological sites in the Moche Valley, Peru, revealed that three major subsistence patterns prevailed between the time of the first permanent settlements (c. 2500 B.C.) and the arrival of the Spaniards (a.d. 1532). The first permanent settlements were predicated on marine resources and gave way gradually to larger inland polities with irrigation agriculture and a non‐marine animal protein source. The final shift saw the development of the Chimu state and associated satellite communities established to provide specific goods and services and linked to the state through an extensive system of redistribution. All three patterns are examined in terms of changes in diet and subsistence, and some effort is made to place them in proper cultural perspective.
Article
The Casma Valley of Peru’s north central coast contains the largest New World structure of its time period---2500 to 200 BC---as well as one of the densest concentrations of early sites. In this detailed and thought-provoking volume, Sheila and Thomas Pozorski date each major early site, assess this important valley’s diet and subsistence changes through time, and begin to reconstruct the development of Casma Valley society. Fifteen sites are surveyed, including Pampa de las Llamas-Moxeke, the earliest planned city in the New World. The Pozorskis then synthesize their own fieldwork and previous work in the Casma Valley to chart its development during the critical time when civilization was emerging. The result: a scenario which is somewhat revolutionary in the context of more traditional views of Andean prehistory. Early Settlement and Subsistence in the Casma Valley, Peru adds substantially to the growing body of evidence that the earliest development of Andean civilization occurred on the coast rather than in the highlands. This volume presents comparative data for students of emerging civilizations worldwide and will be of value not only to Andean and New World archaeologists but also to everyone interested in the emergence of complex societies.
A 6100 yr El Niño record from the Galapagos Islands
  • M Riedinger
  • M Steinitz-Kannan
  • W Last
  • M Brenner
Riedinger, M., Steinitz-Kannan, M., Last, W., and Brenner, M., 1998, A 6100 yr El Niño record from the Galapagos Islands: Geological Society of America Abstracts with Programs, v. 30, no. 7, p. 161-162.
El sitio precerámico Los Morteros
  • M M Cárdenas
Cárdenas, M.M., 1995, El sitio precerámico Los Morteros, Pampa de Las Salinas de Chao: Boletín de Lima, v. 100, p. 45–56.
A chronology of the use of marine resources in ancient Peru
  • M M Cárdenas
Cárdenas, M.M., 1979, A chronology of the use of marine resources in ancient Peru: Lima, Instituto Riva-Agüero, Seminario de Arqueología, Pontificia Universidad Católica del Perú, 30 p.
Incidencia del fenómeno ''El Niño'' sobre los mariscos en el litoral peruano
  • W E Arntz
  • E Valdivia
Arntz, W.E., and Valdivia, E., 1985, Incidencia del fenómeno ''El Niño'' sobre los mariscos en el litoral peruano, in Arntz, W., et al., eds., ''El Niño'': Su impacto en la fauna marina: Callao, Peru, IMARPE, Boletín Extraordinario, p. 91–101.
Great Barrier Reef ''climatic optimum'' at 5800 y BP: PAGES (Past Global Changes) Newsletter
  • M K Gagan
  • L K Ayliffe
  • S Anker
  • D Hopley
  • M T Mcculloch
  • P J Isdale
  • J M A Chappell
  • J Head
Gagan, M.K., Ayliffe, L.K., Anker, S., Hopley, D., McCulloch, M.T., Isdale, P.J., Chappell, J.M.A., and Head, J., 1997, Great Barrier Reef ''climatic optimum'' at 5800 y BP: PAGES (Past Global Changes) Newsletter, v. 5, p. 15.
El Niño during the last interglacial period recorded by a fossil coral from Indonesia: Geophysical Research Letters
  • K A Hughen
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